The invention relates to a fibre-reinforced plastic part.
The functional element is generally a substantially metallic part, particularly with a casing, where relative movements occur, such as a gear or a motor.
The problem of the invention is to avoid the aforementioned disadvantages in a fibre-reinforced plastic part.
In the case of a fibre-reinforced plastic part, the invention solves the set problem in that at least one metallic part is integrated into the fibre-reinforced plastic part.
According to a preferred development, the at least one metallic part integrated into the plastic part serves as a supporting element for a functional element, such as a gear or the like. It has been found that in the connection of a fibre-reinforced plastic part, such as a fibre-reinforced plastic robot arm, to a functional element, such as a gear, as a result of the flow characteristics of the plastic, in certain cases that under high pressures or pressing actions the connections or joints are not stable or resistant and instead tend to loosen. In such a case, according to a particularly preferred development of the invention, on one side of the shoulder or shoulders is provided at least one metallic abutment in each case engaging over several metallic parts and that a functional element is braced from the opposite side of the shoulder or shoulders with the abutment against the front ends of the metallic parts facing the same.
Thus, the pressure arising during the fixing of the functional element by bracing largely acts on the end faces of the metallic parts passing through the shoulder or shoulders and not directly on the plastic shoulders themselves, so that the force and moment transmission takes place via the outer faces of the inserted metallic parts on the plastic part and not via the contact surface of gear and abutment on the fibre-reinforced plastic shoulders of the plastic part. This is assisted in that an independent abutment is not in each case associated with the metallic part traversing the shoulder, so that the number of abutments corresponds to the number of traversing metallic parts and instead several metallic parts traversing the shoulders have a common abutment engaging over the same. In a specific development, in the case of a ring flange-like inner shoulder of the fibre-reinforced plastic part, the abutment can be formed by a steel counterring passed over the entire circumference of the shoulder.
According to a first preferred embodiment of the invention, bracing takes place by means of screws, said screws being cap screws and/or the bracing takes place by screw-nut joints.
In an extremely preferred construction of the invention, several metallic parts engaging through the shoulder or shoulders and an abutment are constructed in one piece with one another. The metallic part is preferably constructed as a sleeve.
According to a further development according to the invention, the abutments and several screws are constructed in one piece with one another and in particular the metallic parts are constructed in one piece with threaded bolts and abutments, the metallic part having a larger diameter than the threaded bolts, so that between the latter and the metallic part is formed a step with a frontal contact surface of the part.
The connection of the metallic part to and in the shoulders of the fibre-reinforced plastic part can take place in various ways. In a first variant, the metallic parts are inserted in openings of the shoulder, the parts being pressed into the shoulder and/or the parts are bonded into the shoulder. Alternatively the metallic parts can be moulded into the shoulder.
Thus, in a specific construction, the parts engaging through the shoulder can be sleeves, which may or may not be constructed in one piece with the abutment and then either the sleeves or preferably openings of the abutment are constructed with an internal thread into which the screws can be screwed from the gear side and on the gear side remote from the abutment there is either a screw head or a lock nut screwed onto the thread located there of a threaded bolt.
Particularly if the abutment and the sleeve-like metallic parts engaging through the shoulder are not constructed in one piece, the abutment can be constructed in one piece with several threaded bolts, which engage through the sleeve-like parts passing through the shoulders and the functional element is braced against the sleeve-like, metallic parts by means of the lock nut screwed down with screw thread on the side remote from the abutment. Finally abutments, the metallic parts engaging through the shoulders and the threaded bolts can be all constructed in one piece and it is then essential that the metallic parts engaging through the shoulder at least over the thickness thereof have a larger diameter than the threaded bolts, so that between the threaded bolts and the metallic parts a step is formed and consequently on the side of the metallic parts remote from the abutment construction takes place with frontal contact surfaces for the functional element. Here again bracing takes place by means of the lock nuts screwed zonally onto the threaded bolts.